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Newton, action at a distance, and propagation speed in the 1600s
:::"Field theory" used to mean what you say, but I think today it connotes a "field" that takes time to travel ... as in "quantum field theory." I don't think a distinction is made between particles or waves; the key distinction is between instantaneous action versus action at the speed of light.--[[User:Aschlafly|Andy Schlafly]] 21:43, 15 November 2009 (EST)
:::"Field theory" used to mean what you say, but I think today it connotes a "field" that takes time to travel ... as in "quantum field theory." I don't think a distinction is made between particles or waves; the key distinction is between instantaneous action versus action at the speed of light.--[[User:Aschlafly|Andy Schlafly]] 21:43, 15 November 2009 (EST)
::::We'll have to agree to disagree. [[User:JacobB|JacobB]] 21:44, 15 November 2009 (EST)
::::We'll have to agree to disagree. [[User:JacobB|JacobB]] 21:44, 15 November 2009 (EST)
:::Could I ask you two to lower the temperature of this a bit? The question of "action at a distance" is one that I was going to work on before all my time got sucked up into the black hole that is the general relativity article. I put out requests to [[User:KSorenson]] and [[User:SaraT]] requesting their input, because they both have expertise in historical matters like this. They both were kind enough to reply. See their talk pages. It seems that "action at a distance" probably didn't refer to transmission of force faster than the speed of light back in the 1600's, because such issues weren't considered important then. And Newton's theory couldn't have been a "field theory" back then, because "vector fields" hadn't been invented. The "gravitational field" got invented later, and Newton's theory became a "field theory" retroactively. Whether Newton's gravitational field propagated faster than the speed of light isn't important; it's a classical (pre-1900) theory. Some people were concerned with this issue, but it's been replaced by GR. And Sara seems to say that Newton's concern over action at a distance was about other issues, namely, force between things not in physical contact. We can say now that it refers to speed, but that doesn't seem to be what the issue was in the 1600s. [[User:PatrickD|PatrickD]] 21:54, 15 November 2009 (EST)